---
layout: "default"
title: "String.UTF8View.Index"
description: "Swift documentation for 'String.UTF8View.Index': A position in a String.UTF8View."
keywords: "String.UTF8View.Index,struct,swift,documentation,samePositionIn,samePositionIn,samePositionIn,successor"
root: "/v1.2"
---

<div class="intro-declaration"><code class="language-swift">struct String.UTF8View.Index</code></div>

<div class="discussion comment">
    <p>A position in a <code>String.UTF8View</code></p>
</div>

<table class="standard">
<tr>
<th id="inheritance">Inheritance</th>
<td>
<code class="inherits">Equatable, ForwardIndexType, _ForwardIndexType, _Incrementable</code>
<span class="viz"><a href="hierarchy/">View Protocol Hierarchy &rarr;</a></span>
</td>
</tr>



<tr>
<th>Import</th>
<td><code class="language-swift">import Swift</code></td>
</tr>

</table>


<h3>Initializers</h3>
<div class="declaration" id="init_-string-index-within_-string-utf8view">
<a class="toggle-link" data-toggle="collapse" href="#comment-init_-string-index-within_-string-utf8view">init(<wbr>_:<wbr> String.Index, within: String.UTF8View)</a><div class="comment collapse" id="comment-init_-string-index-within_-string-utf8view"><div class="p">
    <p>Construct the position in <code>utf8</code> that corresponds exactly to
<code>characterIndex</code>.</p>

<p>Requires: <code>characterIndex</code> is an element of
<code>indices(String(utf8)!)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">init(_ characterIndex: String.Index, within utf8: String.UTF8View)</code>

    </div></div>
</div>
<div class="declaration" id="init_-unicodescalarindex-within_-string-utf8view">
<a class="toggle-link" data-toggle="collapse" href="#comment-init_-unicodescalarindex-within_-string-utf8view">init(<wbr>_:<wbr> UnicodeScalarIndex, within: String.UTF8View)</a><div class="comment collapse" id="comment-init_-unicodescalarindex-within_-string-utf8view"><div class="p">
    <p>Construct the position in <code>utf8</code> that corresponds exactly to
<code>unicodeScalarIndex</code>.</p>

<p>Requires: <code>unicodeScalarIndex</code> is an element of
<code>indices(String(utf8)!.unicodeScalars)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">init(_ unicodeScalarIndex: UnicodeScalarIndex, within utf8: String.UTF8View)</code>

    </div></div>
</div>
<div class="declaration" id="init_within_">
<a class="toggle-link" data-toggle="collapse" href="#comment-init_within_">init?(<wbr>_:<wbr>within:)</a><div class="comment collapse" id="comment-init_within_"><div class="p">
    <p>Construct the position in <code>utf8</code> that corresponds exactly to
<code>utf16Index</code>. If no such position exists, the result is <code>nil</code>.</p>

<p>Requires: <code>utf8Index</code> is an element of
<code>indices(String(utf16)!.utf8)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">init?(_ utf16Index: UTF16Index, within utf8: String.UTF8View)</code>

    </div></div>
</div>





<h3>Instance Methods</h3>
<div class="declaration" id="func-samepositionin_-string">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-samepositionin_-string">func samePositionIn(<wbr>_: String)</a>
        
<div class="comment collapse" id="comment-func-samepositionin_-string"><div class="p">
    <p>Return the position in <code>characters</code> that corresponds exactly
to <code>self</code>, or if no such position exists, <code>nil</code>.</p>

<p>Requires: <code>self</code> is an element of <code>indices(characters.utf8)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">func samePositionIn(characters: String) -&gt; String.Index?</code>
    
    
</div></div>
</div>
<div class="declaration" id="func-samepositionin_-string-utf16view">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-samepositionin_-string-utf16view">func samePositionIn(<wbr>_: String.UTF16View)</a>
        
<div class="comment collapse" id="comment-func-samepositionin_-string-utf16view"><div class="p">
    <p>Return the position in <code>utf16</code> that corresponds exactly
to <code>self</code>, or if no such position exists, <code>nil</code>.</p>

<p>Requires: <code>self</code> is an element of <code>indices(String(utf16)!.utf8)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">func samePositionIn(utf16: String.UTF16View) -&gt; String.UTF16View.Index?</code>
    
    
</div></div>
</div>
<div class="declaration" id="func-samepositionin_-string-unicodescalarview">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-samepositionin_-string-unicodescalarview">func samePositionIn(<wbr>_: String.UnicodeScalarView)</a>
        
<div class="comment collapse" id="comment-func-samepositionin_-string-unicodescalarview"><div class="p">
    <p>Return the position in <code>unicodeScalars</code> that corresponds exactly
to <code>self</code>, or if no such position exists, <code>nil</code>.</p>

<p>Requires: <code>self</code> is an element of
<code>indices(String(unicodeScalars).utf8)</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">func samePositionIn(unicodeScalars: String.UnicodeScalarView) -&gt; UnicodeScalarIndex?</code>
    
    
</div></div>
</div>
<div class="declaration" id="func-successor">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-successor">func successor()</a>
        
<div class="comment collapse" id="comment-func-successor"><div class="p">
    <p>Returns the next consecutive value after <code>self</code>.</p>

<p>Requires: the next value is representable.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">func successor() -&gt; String.UTF8View.Index</code>
    
    
</div></div>
</div>


